Mercedes-Benz Parts Catalog Mercedes-Benz Accessories Catalog Mercedes-Benz Technical Articles Mercedes-Benz Tech Forums
 
Follow Pelican Parts on Facebook Follow Pelican Parts on Twitter Follow Pelican Parts on Instagram Follow Pelican Parts on YouTube Follow Pelican Parts on Pinterest Follow Pelican Parts on Tumblr
  Search our site:    
View Recent Cars  |   Cart  | Project List | Order Status | Help    
 >  >
Installing a New Mercedes-Benz Power Steering Pump
 
Bookmark and Share

Pelican Technical Article:

Installing a New Mercedes-Benz Power Steering Pump

Steve Vernon

Time:

3 hour3 hr

Tab:

$3 to $250

Talent:

**

Tools:

13mm, 17mm and 19mm wrenches, 13mm socket, socket extension, turkey baster, pliers, needle-nose pliers

Applicable Models:

Mercedes-Benz W126 (1981-91)

Parts Required:

New belt, power steering pump

Hot Tip:

Be careful working around your radiator

Performance Gain:

Quiet steering

Complementary Modification:

Replace belt

The Mercedes-Benz W126 has the proud distinction of having 5 different drive belts. There are two belts that drive the power steering pump, and these belts also drive the cooling or water pump. If you are servicing or replacing your pump you do not need to remove the A/C belt, air pump belt or alternator belt to perform these jobs, but I do recommend if you are replacing the power steering pump to replace the power steering belts while you are in there. Also, it is very important to have two good belts driving the pump, if one of your belts goes bad or breaks replace it right away, never run the car with only one belt.

The power steering pump is located on the upper driver side of the engine.

If you are replacing the belts you must first remove the air pump belt, alternator belt and A/C belt, please see our articles on removing and replacing those belts. After those belts are removed, you need to loosen the power steering pump to loosen the belt. There are three 13mm nuts holding it on. Loosen the two 13mm nuts attaching the pump to the front plate. With these loosened but not removed, loosen the 13mm nut on the lower driver side of the pump and then use a 13mm wrench from the back of that bolt to turn the toothed bolt in its gear. It is the same system as the other pumps. Turn the rear bolt counter clockwise to loosen the pump. You can now change the belts.

If you are replacing the pump you will need to remove the two steering lines connected to the pump, one is 17mm and the other is 19mm. Before you remove the lines make sure you get as much fluid out of the reservoir as possible. You can use a turkey baster or small hand pump to suck out as much fluid as you can. With the reservoir empty remove the two lines, some fluid will still drain out so be ready for it. With the fluid and lines removed remove the three 13mm nuts and bolts holding the pump to the bracket.

You can easily replace the filter with the pump in the car by removing the retaining clip holding the filter in place. With the clip and spring removed use a set of needle nose pliers and remove the old filter

Take the pump to your bench and replace gaskets as needed. You will need a rubber wrench to wrap around the pulley to stop it from spinning if you are removing it, you can also try and wrap one of the old belts around it to hold it in place.

Replacing the pump is the reversal of removal. Once you have reconnected the power steering line and filled the reservoir, reattach the battery but DO NOT start the car. With the ignition unlocked turn the steering wheel curb to curb 30 times. This will help purge the air from the system, failure to do this will cause air to be trapped in the system and result in a noisy and improperly working rack. Make sure you fill the reservoir to the correct level as the system is very level sensitive.

This photo shows the route of the two power steering pump and cooling pump belts (red arrows), the location of the power steering pump pulley (green arrow) and the three 13mm nuts and bolts connecting it to the car (yellow arrows, one is hidden).
Figure 1

This photo shows the route of the two power steering pump and cooling pump belts (red arrows), the location of the power steering pump pulley (green arrow) and the three 13mm nuts and bolts connecting it to the car (yellow arrows, one is hidden). Note: most of the front of the car has been removed for demonstration purposes.

If you are replacing the pump or removing it to service the seals you will first need to get as much fluid out of the reservoir as possible.
Figure 2

If you are replacing the pump or removing it to service the seals you will first need to get as much fluid out of the reservoir as possible. If you are just changing the belts or need to move the pump out of the way to work on the engine, you do not need to drain it as long as you leave the lines attached. Remove the reservoir cover by undoing the wing nut on top (red arrow).

Use a turkey baster or small hand pump and remove as much fluid from the reservoir (red arrow) as possible.
Figure 3

Use a turkey baster or small hand pump and remove as much fluid from the reservoir (red arrow) as possible.

Loosen the two 13mm nuts (red arrows) attaching the pump to the front plate.
Figure 4

Loosen the two 13mm nuts (red arrows) attaching the pump to the front plate.

On the lower driver side of the pump use a 13mm wrench to loosen the front bolt (red arrow), and then working from the back turn the toothed bolt in its gear (yellow arrow).
Figure 5

On the lower driver side of the pump use a 13mm wrench to loosen the front bolt (red arrow), and then working from the back turn the toothed bolt in its gear (yellow arrow). It is the same system as the other pumps. Turn the rear bolt counter clockwise to loosen the pump.

If you are replacing the pump you will need to remove the two steering lines connected to the pump, one is 17mm and the other is 19mm.
Figure 6

If you are replacing the pump you will need to remove the two steering lines connected to the pump, one is 17mm and the other is 19mm. Before you remove the lines make sure you get as much fluid out of the reservoir as possible. You can use a turkey baster or small hand pump to suck out as much fluid as you can. With the reservoir empty remove the two lines, some fluid will still drain out so be ready for it.

You can easily replace the filter with the pump in the car by removing the retaining clip (red arrow) holding the filter in place.
Figure 7

You can easily replace the filter with the pump in the car by removing the retaining clip (red arrow) holding the filter in place.

With the clip and spring removed use a set of needle nose pliers and remove the old filter (red arrow).
Figure 8

With the clip and spring removed use a set of needle nose pliers and remove the old filter (red arrow).

Bookmark and Share
Comments and Suggestions:
Ximmaster Comments: Didn't find any tensioning bolt at all, was trying to lever like you say - no luck either. The bar doesn't fit anywhere strong enough so I could tight it and fix in that position.
April 22, 2016
  Followup from the Pelican Staff: Look at how it pivots, find the pivot and the leverage point. YOu will have to move it to the tensioned position manually. - Nick at Pelican Parts  
Ximmaster Comments: Hi
What if there is no toothed bolt with it's gear on the back of the pump pointed by yellow arrow on fig 5 ? How do I change the tension in this case? There is no mechanism there at all, just the flat head on the opposite side of lower 13 mm bolt... And this flat head is not twist-able, it sits tight in it's place.
April 22, 2016
  Followup from the Pelican Staff: There should be a tensioning bolt to tighten. If not, you may have to lever it tight, hold, then tighten. - Nick at Pelican Parts  
gmkjr Comments: Before loosening the belts, loosen the bolt on the pulley a bit, it will be much easier when the belts are holding the pulley and shaft stationary.
May 14, 2015
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
gmkjr Comments: After removing the pump from the engine, draining all the fluid, removing the filter, and cleaning the outside of the pump to avoid contamination during handling, I removed the pulley by supporting the edge of the pulley on a large piece of wood, and tapping on the mounting nut with a soft mallet, being careful to avoid bending the pulley. After removing the pulley, remove the woodruff key from the slot in the shaft.

To remove the seal, I carefully stuck a screwdriver through the old seal, using light taps from my soft mallet, then gingerly used the screwdriver blade to pull the old seal out of the pump. Be careful to avoid marring any surfaces of the pump shaft or housing. I then inserted the new seal by hand, and then pressed it into place using a 19 mm socket, beginning with hand pressure, and then light taps with a soft mallet. The face of the seal should be flush with the front face of the pump housing.
February 19, 2015
  Followup from the Pelican Staff: Thanks for sharing your installation process and experience. These type of comments add so much to the Pelican tech community.
- Nick at Pelican Parts
 
Steve Comments: 1991 SL 500. How do i replace the seals on my power steering pump
July 1, 2013
  Followup from the Pelican Staff: Sorry, we do not have a DIY on this yet.
-whunter-
 

  Search our site:    

View Cart & CheckOut | Project List | Order Status |  Help    

 

[Home] [Customer Service] [Shopping Cart] [Project/Wish List]
  [Privacy Statement]  [Contact Us] [About Us] [Shipping] [Careers]

Copyright © Pelican Parts Inc. -    DMCA Registered Agent Contact Page

Page last updated: Wed 12/7/2016 02:28:01 AM